Field of the Invention
The present invention relates to an image processing apparatus and method, an image projection apparatus, a printing apparatus, and an image printing and projection system, and more particularly to a technique for superimposing a printed matter and a projected image.
Description of the Related Art
A printed matter printed with a printing apparatus such as an inkjet printer, an offset printer or the like is usually viewed under a viewing environment light such as ceiling lighting. In other words, printed matter is illuminated with a viewing environment light, and a user observes the reflected light of the printed matter. Therefore, the dynamic range of the display luminance of the printed matter is determined by the brightness of the viewing environment light, the reflectance of the paper, and print quality.
On the other hand, in recent years, dynamic range expansion technology called HDR (High Dynamic Range) control has rapidly advanced in image sensing apparatuses that take pictures. Japanese Patent Application Laid-Open No. 2016-174315 discloses a technique in which an image signal from an image sensor such as a CMOS sensor is processed while compressing luminance as low as possible so that the reproducibility of the luminance, color, and contrast ratio approach the dynamic range of the human eye.
In addition, Japanese Patent No. 5153566 discloses a technique of performing HDR viewing of an HDR image using a printed matter, wherein by projecting an image on a printed matter with a projector or the like and superimposing it on a printed image, display luminance and color dynamic range are increased. Since printed matter can be produced at a very low cost and high definition images can be printed, it is possible to display a high quality image with a lower cost than using a high resolution projector or a liquid crystal display compatible with HDR display. Specifically, by projecting an image on a black-based printed portion with a low reflectance by a projector or the like, the black luminance level is lowered and a contrast ratio that is several stages higher than a contrast ratio expressed by the projector alone can be expected, and therefore, it is suitable for HDR expression. Picture exhibition, advertisement, art, etc. are considered as applications of such a display method.
However, in a case where an image is projected onto a printed matter by a projector or the like and superposed on an image of the printed manner as described in Japanese Patent No. 5153566, if the spatial frequency (perceived resolution) of the projected image is low, the resultant image may be sometimes blurrier than expected.